Process and apparatus for the manufacture of smokeless powder



6, 1940- EM. sYMMEs 2. J

PROCESS AND APPARATUS FOR THE MANUFACTURE OF SMOKELE$S POWDER FiledMarch 29, 1959 ERNEST M. SYMMES INVENTOR.

Ma. 9;. Mom um g ATTORNEY.

Patented Aug. 6, 1940 UNI.

PROCESS AND APFARATUS FOR THE MANU- FACTURE F SlWQKELESS POWDER ErnestM. Symmes, Wilmington,Del., assignor to Hercules Powder Company,Wilmington, Dei., a corporation of Delaware Application March 29,

7 Claims.

This invention relates to an improved process of manufacturing colloidedsmokeless powder, and more particularly to an extruding die forsmokeless powder which is resistant to the abrasive action of thepowder.

Heretofore, in the manufacture of smokeless powder, nitrocellulose hasbeen colloided by the use of solvents, for example, ethyl alcohol-ethylether or acetone-ethyl ether mixtures, to a dense colloid, and, ifdesired, with the addition of a liquid explosive such as, for example,nitroglycerine or the like. This plastic colloid has been extrudedthrough dies to form strands of the desired diameter which may, ifdesired, have one or more central perforations therein and the resultingstrands cut into grains.

The object of this invention is to provide a die for use in extrudingsmokeless powder that is resistant to the abrasive action of the powder.A further object of this invention is to provide a die that willalleviate the need of continually changing dies used in the extruding ofsmokeless powder strands. Further objects will appear hereinafter.

25 In the manufacture of smokeless powder the dies through which theplastic colloid is pressed have been made heretofore of hardened steel.I have found that when dense colloided smokeless powder is made upusing, instead of fresh fibrous 50 nitrocellulose, a ground or otherwisedisintegrated scrap smokeless powder suitably softened to a plasticcolloid by the use of solvent mixtures, such as ethyl ether-ethylalcohol or ethyl alcoholacetone, an extreme wear of the hardened steeldies occurs. For example, when pressing 285 pounds of colloidedsmokeless powder through a steel die into 155 mm. Howitzer powderstrands, the die enlarged from .0675 to .0720 inch, thus rendering thedie useless and requiring frequent and costly replacements. Harder steelis not favorable on account of brittleness and lack of strength, butmuch to my surprise I have found that I may use a comparatively softmetal and produce a die that has many advantages over the hardened steeldies.

Having now indicated in a general way the nature and purpose of thisinvention there follows a more detailed description of the preferredembodiment thereof, with reference to the accom- 55 cated within thebody of the die. The die 1 is panying drawing in which: Figure 1 is aneleva-' 1939, Serial No. 264,784

(or. 1s 47) of; heavy construction to withstand the pressure necessaryto cause the smokeless powder colloid to ,extrude through the hole 2.The die I is designed to havea funnel shape entrance 3 to the die hole2, as this type designv greatly facilitates The die i of this inventionas will be obvious to, those familiar with the art may be fitted withpin to produce perforated powder grains if so desired and this pin willbe included as part'of the adapter.

Now in accordance with this invention, I have produced a die from thecomparatively soft metal nickel which is in an approximately pure state,but contains traces of Co, C, Si, Mn, Fe, and Cu, and has a 5C Rockwellhardness. It is to be noted that the hardened steel dies now in use haveapproximately a 640 Rockwell hardness, which, on a comparative basis,would class the die metal of this invention as very soft.

It is wholly unexpected and unpredictable that a comparatively softmetal would have a longer life and withstand the abrasive actiondeveloped in pressing smokeless powder better than the hardened steeldies, but that such is the case is apparent from the results shown inthe table below.

*Composition of the nickel used, approximately pure, but has traces ofC, Si, Mn, Fe, Cu, and Co, and a Rockwell hardness of 5C.

It of a die made from the soft metal of this invention would beapproximately twice that of the hardened steel dies now in use. Such anincrease in the life of a die provides many advantages and improvementsover the art. Thus, with the dies of this invention, more powder may beproduced within a given period of time, since the need of changing diesis reduced to one-half;

is noted from the table that the life further, the ballistics of thepowder produced are more uniform, since the diameter of the powdergrains is held more constant; and still further, there is an addeddegree of safety in operation, since each change of dies eliminatedprevents possible accidents due to the friction of removing the diesfrom the die holders.

I do not limit my invention to any particular kind of a dense colloidedsmokeless powder, but I may use my invention in the manufacture ofsmokeless powder prepared by the use of fibrous nitrocellulose which,while not as severe on the die as smokeless powder prepared by the useof reworked smokeless powder, naturally causes a considerable wear onthe dies. I may also use my invention in the preparation of any desiredshape or form of strand of dense colloided powder. These strands ofcolloided powder may be solid or may have a single perforation, as inthe case of small arms powder, or may be multi-perforated, as in thecase of cannon powder. I may further use my invention in the preparationof so-called Pym-powders, which contain no nitroglycerin, or I may usemy invention in they preparation of double base smokeless powders, whichcontain nitroglycerin.

It will be understood that the details and examples given hereinbeforeare illustrative only, and in no way limiting on my invention as broadlydescribed hereinbefo e and in the appended claims.

What I claim and desire to protect by Letters Patent is:

1. In a method of preparation of dense colloided smokeless powder, thestep consisting of pressing a hard and tough nitrocellulose colloidthrough a forming die consisting of nickel.

2. In a method of preparation of dense colloided smokeless powder, thestep consisting of pressing a hard and tough nitrocellulose colloidthrough a forming die consisting of nickel, said die being constructedto produce a tubular powder strand.

3. In a method of preparation of dense colloided smokeless powder, thestep consisting of pressing a hard and tough nitrocellulose colloidthrough a forming die consisting of nickel, said die being constructedto produce a multi-tubular powder strand.

4. In a method of preparation of dense colloided double base smokelesspowder, the step consisting of pressing a hard and tough double basenitrocellulose colloid through a forming die consisting of nickel.

5. A single hole die for smokeless powder press, said die consisting ofnickel, and constructed to produce multi-perforated strands of pressedmaterial.

6. A single hole die for smokeless powder presses, said die comprisingessentially nickel and constructed to produce strands of smokelesspowder.

7. A single hole die for smokeless powder presses, said die comprisingessentially nickel and constructed to produce hollow strands ofsmokeless nowder.

ERNEST M. SYMMES.

